Presence of second mesiobuccal canal of permanent maxillary first molars is related to the existence of multiple roots in permanent maxillary first premolars: A cone-beam computed tomographic study in a Taiwanese population.

BACKGROUND/PURPOSE: Understanding root and canal morphology is critical for successful endodontic treatment. Detecting predictors of a second mesiobuccal (MB2) canal in permanent maxillary first molars (PMFMs) may improve diagnostic accuracy. This study examined the relationship between root number of permanent maxillary first premolars (PMFPs) and MB2 occurrence in PMFMs in a Taiwanese population. MATERIALS AND METHODS: CBCT scans from 645 patients were reviewed, and 188 met the inclusion criteria, yielding 752 teeth (376 PMFPs, 376 PMFMs). Root number and canal morphology were classified using Vertucci's system. MB2 prevalence and bilateral symmetry were assessed. Associations between PMFP root number and MB2 occurrence were analyzed with chi-square tests and multivariable logistic regression adjusted for sex, age, and side. RESULTS: Among PMFPs, 60.9 % had one root, 37.5 % had two roots, and 1.6 % had three roots. In single-rooted PMFPs, the most common configurations were Types I, III, IV, and II. In PMFMs, the mesiobuccal root most frequently showed Type I (42.0 %), followed by Type IV (30.8 %) and Type II (23.6 %). Males had a higher prevalence of multi-rooted PMFPs and MB2 canals than females. Logistic regression revealed that multiple-rooted PMFPs were independently associated with MB2 occurrence in PMFMs, with an adjusted odds ratio of 2.081 (P < 0.001). Bilateral symmetry was high in both PMFP root number (81.4 %) and MB2 presence (85.1 %). CONCLUSION: Multiple-rooted PMFPs were strongly correlated with MB2 occurrence in PMFMs. PMFP morphology may serve as a predictive indicator for MB2 detection, enhancing diagnosis and treatment planning while no CBCT usage.